Category: Question & Answer

(a) Explain how lubricating oil can be tested onboard.

Answer:

L.O can be tested on board by using Maker’s supplied test kit , which can give the result whether it is safe for further use or not.
For L.O test , sample oil must drawn out from correct point , such as from test cock or from pump’s discharge pressure gauge connection. It should not be drawn out from , filter out let and purifier out let .
Sample oil must be taken with standard plastic tube with seal for both on board test and Lab. analysis.Read more

Q. (a) Explain why regular testing of water in auxiliary boiler is advisable(b) How to take correct sample(c) Discuss what factors are necessary when measured value differ appreciably from desired value in each test.(d) Give reasons for the situation when alkalinity is found to have fallen unaccountably.

Answer:

(a) For the well boiler operation, boiler water should be tested regularly and accurately. Then correct chemical treatment should be followed based on the test results for the following reasons.

– To keep the boiler water in alkaline condition
– To precipitate all scale forming , both dissolved and suspended salts in the boiler water , in the forms of removable and non-adherent sludge.
– To remove dissolved oxygen , carbon dioxide and other gases
– To produces substances which will be well below the limits for carry over , foaming and priming..Read more

It is complete failure of the UMS, bridge control and data logging system has failed and the main engine is needed to run on manual control and monitoring.(a) State with reasons six main items of data, which require to be monitored and recorded manually.(b) Explain how a watch keeping system should be arranged to provide for effective monitoring and control of the main engine.(c) Explain how the staff will be organized to maneuver the engine safely. State the machinery plants at which attentions are required during maneuvering.

Answer:

(a) When M.E to be put on manual control and monitoring, the following six main items of data to be monitored and recorded manually.

1. Cooling water system.
It is required to prevent the thermal stress and thermal loading on the engine. Engine may breakdown in severe
Case.
– Jacket water temperature and pressure
– Piston cooling temperature and pressure ( If water cool )
– Sea water temperature and pressure ( For Coolers & condenser ) …. to be checked & recorded.Read more

(By Kamal Hossain, Chief Engineer)

Viscosity

High viscosity of fuel may cause the following effects being using high temperature heating
– Fouling of Oil heater
– Gassing of Fuel
– Thermal expansion to fuel pump and injector component leading to seizure or sticking
– Clogging of filterRead more

Scale formation and corrosion are the main two factors that determine the efficiency of the internal parts and as well as lifetime of the boiler. Badly corroded and scaled boiler can fail within very short time.

SCALE FORMATION IN BOILER

Depending upon the sources boiler water contains various types of salts and impurities. Under operating conditions all the salts comes out of the water. These salts cause formation of scale inside the boiler. The more the water contains solids and salts the more the boiler is prone to scale formation. Read more

Dry docking survey is to be done every 2 ½ years interval , 2 times in 5 each year cycle , called annual docking and special docking survey. Special survey is carried out every 5 years interval.

As a Chief Engineer of a vessel , he must study the time of dry docking due , verify annual or special , and prepare documents & defect list to be repaired , at least 3 months priority for easy and efficient supports from ship company.

Preparation of Documents:

The necessary plans , drawings , instruction manuals , service records of previous docking to be collected and kept ready . Copy of plans and drawing to be sent to dockyard on request.

Watch Keeping in Engine Room:

Image Credit: www.jamstec.go.jp

A. Handing over a watch:

Engineers on ships perform their duties in rotational shifts, each having fixed and equal number of hours. This work shift, also known as a watch, needs to be carried out in an efficient manner to ensure the safety of life and property at sea. The normal watch keeping schedule and responsible watch keeping engineers in a fully manned engine room:
0800-1200——4/E, 2000-2400—-4/E
1200-1600——3/E, 2400-0400—-3/E
1600-2000——2/E, 0400-0800—-2/E

A watch keeping engineer should take extra care while handing over the watch to the incoming watch keeping engineer to make sure that the ship runs safely and smoothly.

It is necessary that the right information is passed to the incoming engineer by the engineer on watch so that he can concentrate on his watch and perform more demanding and important jobs.

Handing over of the watch should be carried out according to the instructions provided by the chief engineer’s standing orders and company’s instructional manual. It should be done very sincerely and honestly so that the watch keeping becomes smoother and continuation of any kind of work is not affected on the ship.

The following things need to be informed to the reliving officer:

Special orders related to any ship operation from bridge or the company

Standing orders from the chief engineer

Special mode of navigational operation of ship in case of emergency situation, damage, icy, or shallow water etc

In case there is any kind of maintenance work being carried out in the engine room by other engineers and crew members then their work location, details of machinery under maintenance, and information of authorized person and crew members should be provided.

Boiler Safety Valves protect the boiler from over pressurisation. As per the requirements, at least two safety valves should be fitted to the boiler and both are mounted on a common manifold with a single connection to the boiler. Boiler with super heater, normally three safety valves are fitted; two to the boiler drum and one to the superheater. The superheater must be set to lift first to ensure a flow of steam through the superheater.

Improved High Lift Boiler Safety Valve:

Fig: Improved Highlift Boiler Safety Valve

The sketch shown is improve high lift safety valve . The are usually mounted 2 Nos. on a single chest. Valve , seat , spindle , compression screw and bush are made of non-corroded metal and valve chest is made of cast steel.
This valve improve than other type as because:

Fire Hose:

At least one fire hose for each of the hydrants and hose shall be used only for extinguishing fires and testing purposes. (Passenger Ship)

One for each 30m length of ship and one spare, but not less than 5 in all. (Cargo Ship = or > 1000GT) and ship carrying dangerous goods shall be provided 3 hoses & nozzles in addition to those required above and cargo ship <1000GT, shall be provided no less than 3 fire hoses & nozzles.

The stern tube is a hollow tube-like structure at the stern or rear part of the ship. A ship needs the propeller to drive it forward in water. The propeller, located outside the ship, needs to be connected to the engine inside the ship’s engine room. The propeller shaft is used for connecting the ship’s engine and the propeller. The stern tube is a narrow hole in the hull structure at the rear end (aft peak) of the ship, through which the propeller shaft passes and connects the engine and propeller.

Stern tube bearings serve two main functions:
1. To properly connect the propeller to the ship
2. To keep water from leaking into the stern tube (and lubricant from leaking out)Read more

Definitions and Ship’s Dimensions

Hull:
The structural body of a ship including shell plating, framing, decks and bulkheads. Afterbody :
That portion of a ship’s hull abaft midships. Forebody:
That portion of a ship’s hull forward midships. Bow :
The forward of the ship Stern :
The after end of the shipPort :
The left side of the ship when looking forwardStarboard :
The right side of the ship when looking forwardAmidships:
point midway between the after and forward perpendicularsRead more

The following engine room spaces are very hazardous on-board the ship and therefore, a special ventilation arrangement should be provided for safe entry:

Ventilation Arrangement for Confined Spaces of Ships:

(a) CO2 storage compartment
– CO 2 compartment is situated on open deck , well ventilated and easily accessible .
– Its compartment door is opened outward.
– Boundaries between CO2 compartment should be watertight.
– Ventilation louver is fitted at the bottom near the floor , for the leaky CO2 to release to atmosphere because CO2 is more heavier than normal air.
– In some ships , exhaust fan is provided . Its suction is taken from bottom of the compartment and lead to open air deck . Exhaust system is separately provided from others.
– In some modern built ships , CO2 leakage warning alarm is providedRead more

About 30% – 34% of Fuel Energy input to engine are discharged to Exhaust Gas, as Thermal Energy.

This thermal energy is converted into useful work in Exhaust Gas Boiler.

Cochran Exhaust Gas Boiler:
1. A double-pass, vertical type, in which Exhaust gases from ME pass through 2 banks of tube.
2. Served as an efficient silencer, when the boiler is in use.
3. A separate Silencer, always fitted along with exhaust gas boiler, to be used when the boiler is generating more steam than required.
4. All or part of exhaust gases can be directed to the Silencer and atmosphere, without going through the boiler.
5. Working Pressure is around 7 bars.

Composite Boiler (Composite type Cochran boiler):

1. If Exhaust Gases and Oil fire can be used at the same time, it is termed Composite Boiler.
2. In double-pass, composite type Cochran Boiler, it provides a separate tube nest for exhaust gas passage, situated immediately above the return tube nest from Oil-fired Furnace.
3. Exhaust gases from Oil-fired Furnace and ME; pass through the tubes, which are surrounded by boiler water.
4. Separate Uptakes provided for Exhaust Gases and Oil-fired Smoke.
5. Heavy Changeover Valves are fitted, to divert the gases straight to the funnel, when desired.Read more

Viscosity Index, VI:
1. The rate of change of viscosity of an oil, in relation to change of temperature.
2. Oil of low VI has greater change of viscosity with change in temperature,
than the oil of high VI.
3. For crankcase oil, VI is between 75 – 85; For cylinder oil, VI is 85.
4. Highest VI of mineral oils is about 115 and with special additives, this may be raised to about 160.
5. Hydraulic oils, used in remote control hydraulic circuits must have very high VI; otherwise erratic response to the controls can be troublesome. (Telemotor hydraulic system oil has VI of 110.)Read more

Survey:

Authorised independent examination, investigation, and inspection, measuring or testing of ship structure, machinery and equipment, done and supervised by Surveyors appointed by regulatory or commercial organisations.

Their functions:
1. To ensure that ship is soundly constructed and the standard of construction is maintained.
2. Carried out Statutory Survey on behalf of the Administration regarding the ship safety and prevention of pollution of marine environment.Read more

How does emergency alarm ring?

Ans: Continuous ringing of bell. Emergency situation is explained at the muster situation. Pattern of Emergency signal is indicated on Muster list

Q. Explain the Fire Tube and Water Tube Boiler.

Fire Tube Type: Due to simple design of the tubes effective heat transfer takes place, but periodical cleaning/maintenance is slightly difficult. Soot blowing is not effective for regular cleaning. Used with low pressure boiler

Water Tube type: In comparison to fire tube type heat transfer is not so so effective. Gas side cleaning is easier, sometimes fixed water spray design is used for cleaning. Soot blowing is effective , used with medium – high pressure boiler

Q. What is Ogee ring?

Ans: Connects the bottom of the furnace to the boiler shell plating.Read more

The International Management Code for the Safe Operation of Ships and for Pollution Prevention (International Safety Management (ISM) Code).

What is I.M.O. Convention ?

Conventions are chief instruments of IMO, being binding legal instruments, regulating some aspect of maritime affairs of major concern to IMO e.g. safety of life at sea (SOLAS) or marine pollution (MARPOL).

They are identified by name and the year of adoption by the Assembly, Such as the International Convention on the Safety of Life at Sea, 1974.

May have detailed technical provisions attached in annexes, such as six annexes to the MARPOL convention, each dealing with a different aspect of marine pollution.

How many conventions are there ?

About 50 ? Though checked up to 1998, 25.

What is a Protocol ?

A treaty instrument which makes major modification to a Convention which has been adopted but not yet in force. The Protocol usually speeds up the Convention’s entry into force. e.g. MARPOL 73/78, SOLAS 74/78